1. Field of the Invention
This invention relates generally to medical catheters, and more particularly to catheters for providing access to blood vessels.
2. Description of Related Technology
A significant problem encountered during the administration of intravenous solutions to patients, particularly over extended periods of time, is leakage of the intravenous fluid from the vein into which it is introduced. This leakage usually results from internal laceration of the vein by an indwelling catheter or butterfly needle having a sharp tip. Subsequent leakage of solution and soft tissue damage can become a major problem, particularly if the drug being introduced into the vein is a local irritant or soft tissue vesicant.
Sharp-tipped steel scalp-vein or "butterfly" needles having flexible wings which can be taped in position on the skin of a patient are commonly used for continuous subcutaneous and intravenous medication delivery. The sharp tip of the needle can cause prolonged local irritation and pain, which may be compounded by irritation from the drug being delivered. Winged catheter assemblies may comprise a flexible cannula having a needle inserted in the cannula. The needle is used to insert the catheter into a vessel, but must be removed after the catheter is inserted. A winged infusion device comprising a catheter having a retractable sharp needle is disclosed in Dorr, U.S. Pat. No. 4,627,841, the disclosure of which is hereby incorporated by reference. The Dorr '841 patent device includes a spring for biasing a needle hub and a catheter hub towards each other and a wedge for separating the hubs. The present invention is an improvement over the Dorr '841 device in that it includes an elastomeric housing that biases a catheter hub and a needle hub towards each other. No spring or wedge are required for the present invention.